Electric switch



W. C. KARCH ELECTRIC SWITCH Jan. 16, 1962 2 Sheets-Sheet 1 Filed Sept. 29, 1960 Jan. 16, 1962 w. c. KARCH 3,017,471

ELECTRIC SWITCH Filed Sept. 29, 1960 2 Sheets-Sheet 2 15 16; 16a /Z0d 19 l INVENTOR. z/flldf C! M Baum Patented Jan. 16, 1962 3,017,471 ELECTRIC SWITCH Walter C. Karch, Milwaukee, Wis., assignor to Square D Company, Park Ridge, ill, a corporation of Michigan Filed Sept. 2%, 1960, Ser. No. 59,363 6 Claims. (or. zoo-76 This invention relates to electrical switches of the snapacting type in which a contact carrier is movable from on to off positions with a snap action by a dead-center spring consequent upon initial movement of the carrier toward the selected position, either by a suitable actuating means or by a return spring.

Switches of this character are sold in a highly competitive market and it is necessary, therefore, that the working parts thereof be capable of being manufactured and assembled with a minimum of manual labor. Further, it is equally important that the switch be small and compact in relation to its rated maximum voltage and current, yet strong enough to operate several million times with a snap action without breakage or damage to the parts. Again, such switches frequently are used for carrying relatively high currents that heat the contact bridging conductor elements and, accordingly, the movable contact carrier must be capable of withstanding the heating effects caused by such currents in the contactors and conductors within the switch without deterioration thereby.

The object of the present invention is to provide a snap 3 action switch meeting these requirements.

For the purposes of illustration, the invention herein is disclosed in connection with a double-pole, doublethrow snap acting switch employing a movable carrier and two contact assemblies which can be installed readily on the carrier and removed therefrom and replaced readily for servicing, yet which, when installed, are retained effectively in proper position for operation over long periods of use. The manner in which the invention can be incorporated in other types of switches will be readily 4 apparent from the illustrative example in which reference is made to the drawings, wherein:

FIG. 1 is an isometric view of a switch embodying the principles of the present invention;

FIG. 2 is an exploded isometric view of the switch illustrated in FIG. '1, showing the parts in the position for assembly;

FIG. 3 is an enlarged top plan view of the switch illustrated in FIG. 1 with the cover removed, and with the upper stationary contacts and movable contact assembly removed in the right-hand portion;

FIG. 4 is a front elevation of the structure illustrated in FIG. 3 with the cover plate in place, part of the structure being shown in section for clearness in illustration, as indicated by the lines 4-4 in FIG. 3;

FIG. 5 is an enlarged top plan view of the carrier frame of the present invention; and

FIGS. 6 and 7 are vertical sectional views taken on the lines 66 and 77, respectively, of FIG. 5;

FIG. 8 is a fragmentary isometric view of the pushbutton and carrier, with the contact bridges and mounting springs, illustrated in FIG. 2, but with the carrier inverted;

FIG. 9 is an enlarged cross sectional view of the carrier and bridging conductor taken on the line 99 in FIG. 8;

FIG. 10 is an enlarged top plan view of a bridging conductor; and

FIG. 11 is a longitudinal sectional view of the bridging 7 conductor and is taken on line 1111 of FIG. 10.

Referring to the drawings, the switch comprises a hollow body i normally closed by a suitable cover plate 2.

The body is preferably made of insulating material and embedded in each end is a pair of metal conducting sleeves 3. A metal conductor 4 is fastened fixedly by a suitable screw 5 to each sleeve and on its underface carries a stationary contact 6. The other end of each sleeve 3 carries a screw 7 which is accessible for operation through the bottom of the body of clamping a wire to the sleeve 3 and thereby effecting an electrical connection to the upper stationary contact 6. Two stationary contacts 6 are provided at each end of the body and are spaced laterally of the body from each other. A pair of lower stationary contacts 9 is arranged at each end of the body. Each pair is secured in the body by a suitable conducting sleeve 10 which, in turn, receives a screw 11 for connecting a wire thereto. Each lower stationary contact 9 of each pair is arranged beneath and in alignment with a corresponding upper contact 6 of the pair thereabove.

In operation of the switch, it is desirable to bridge the upper contacts 6 of each pair by a bridging conductor in one position of the switch, and to bridge the lower contacts 9 by the same conductor in another position of the switch. For this purpose, movable contact assemblies are provided, one for each set of aligned upper and lower stationary contacts.

Each assembly comprises a bridging conductor element 1.2 and upper and lower contacts 13 and 14 thereon, the contacts 13 being cooperable with the contacts 6 and the contact 14 being cooperable with the contacts 9, of their associated set.

In order to move the assemblies to different contact making and breaking positions, a carrier 15 is provided and is floatingly mounted in the body. For supporting the carrier in the body for movement to cause the assemblies to make and break contact with respect to the different stationary contacts, an actuator 16 is mounted in the body 1 for movement upwardly and downwardly. The carrier 15 preferably is in the form of a frame having a central opening 17. The actuator 16 has portions in the form of depending legs 16a which extend through the opening 17 and through a pair of oppositely facing notches 18 in the carrier 15 and are received in suitable guideways 19 in the body 1. The clearance is provided between the legs 16a and the walls of the notches 18. The guideways guide the actuator in a lineal path upwardly and downwardly relative to the cover 2.' The actuator 16 also has a portion in the form of a pushbutton 2% having a reduced diameter portion and a shoulder Zita. The reduced diameter portion extends through a suitable opening 2a in the top cover 2 and is accessible for operation by hand or for connection to a suitable operating mechanism for operating the switch. The shoulder Ztlw is engaged by the underside of the cover 2 and the button is held partially depressed thereby.

It is desirable that the carrier 15 be moved, with a snap action, downwardly upon depression of the button 20 and upwardly upon upward or return movement of the button 20. The actuator 16 is moved upwardly by a return spring 21 when the button 20 is released. In order to provide a snap action for causing the frame to snap upwardly when the button is depressed and snap downwardly when the button is returned, dead center springs are provided and interconnect the actuator and carrier.

For this mounting, the carrier 15 is provided at opposite ends with internal shoulders 23. correspondingly, the actuator 16 is provided at opposite sides with notches 24. Each notch 24 is adapted to receive one end of a snap-action, dead-center spring 25, of which the other end is bent, as indicated at 26, to accommodate the adjacent shoulder 23 on the carrier. Thus, each spring is stressed resiliently in position between one of tare shoulders 23 and the base of the adjacent notch 2 and is held so engaged by the forces imposed by its own stressed condition. Each spring 25 preferably has a loop portion 27 its ends to assist in the snap action by permitting the length of the springs 25 to be reduced as they approach and pass dead center. The normal location of the shoulders 23 and the notches 24 when the button 2% is held in the partially depressed position by the engagement of the cover with the shoulder 26a, is such that the springs 25 bear downwardly on the carrier 15, the ends of the springs 25 in the notches 24 being upwardly above the level of the shoulders 23. This holds the carrier so that the lower contacts 14 of the bridge are pressed into firm contact with the lower contacts 9. When the button 26 is fully depressed, the bases of the notches 24 are below the level of the shoulders 23. Thus, when the button Ztl is depressed, the ends of the springs received in the notches 24 are moved to a position below the level of the shoulders 23 and the springs exert their snap action force so as to lift the carrier upwardly. When again the button 2%? is released and returned by the spring 21, the base of the notches 24 move to a position above the level of tne shoulders, whereupon the springs exert their snap action force to move the carrier 15 downwardly.

The manner of mounting the bridging element 12 on the carrier 15, with which feature the present invention is particularly concerned, will be described. The carrier preferably is elongated endwise of the body and comprises side frame members 3% and end frame members 31 and is supported by the springs with one face of the frame upwardly and the end frame members 31 facing toward the ends of the body l. The bridging conductors 12 are connected to the end frame members 31 and since the manner of attachment of each thereto is the same, the attachment of only one will be described in detail.

Referring to FIGS. 5 through 7, on each end frame member 31 is a ledge 32 which has an upwardly open trough 33, the trough being defined by a supporting surface 34 on which one of the conductor elements 12 rests fiatwise and which extends transversely of the length of the frame, as illustrated. The element 12 is constrained from displacement laterally of the trough, endwise of the frame, by the side walls of the trough which provides suitable shoulders 35 and 35.

In order to hold the conductor element 12 in the trough, a suitable snap-acting spring C-clarnp 37, having an upper arm 37a, a lower arm 37b, and a base 37c, is provided. This C-clamp is adapted to be received on the frame, and to be moved endwise of the frame and transversely of the trough, open end foremost, into operating position after the conductor 12 is disposed in the trough. In its operating position, it spans the upper open side of the trough and thus prevents displacement of the conductor 12 therefrom through the open side. A suitable socket 38 is provided in the end frame member 31. This socket may be in the form of a small upright groove which has its open side facing endwise of the frame toward the trough and which is open at its upper end, indicated at 39, at the top face of the frame. The ledge portion of the frame is provided at the outer end of the frame with an upright trough 4% which has its open side facing outwardly endwise of the frame. The trough 40 is open at the top end, indicated at 41, and is open at the bottom end, indicated at :2, for engagement at the bottom end with the open end of an inverted trough 43. The trough 43 is formed in the end frame member in spaced relation below the supporting surface 34 of the trough 33. The inverted trough 43 extends in a direction transversely of the trough 33 and is adapted to receive endwise, and accommodate, the lower arm 37b of the C-clamp 37. Near the inner end of the trough 43 is a recess 44 which provides a shoulder over which a detent 45, formed on the free end of the lower arm 37b of the C-clamp, snaps when the clamp is installed and behind which the detent 46 seats to prevent accidental withdrawal of the C-clamp closed end foremost.

The upper surface of the outer portion of the frame which defines the shoulder 36 is preferably flush with the top of the conductor element 12 when the conductor element 12 is seated in the trough 33. Thus, as the clamp 37 is pressed into operating position, open end foremost, the upper arm 37a slides across the top of the surface 46 and across the top of the conductor element 12 until its free end seals in the socket or trough 39. At the same time, the lower end 37b slides along the trough 43 until the detent $5 on its free end interengages with the recess 44.

Thus, the clamp holds itself in operating position and prevents its own accidental withdrawal closed end foremost. Also, it holds the element 12 in the trough 33. It is to be noted that the lower arm 37b and the base 370 of the G-clamp 37 are deep seated in their notches and protected by the notched side walls against accidental displacement. The C-clamp can be readily removed for removal and replacement of the movable contact assembly, when desired.

Referring to FIGS. 8 through ll, the switch is shown with the carrier 15 and bridging conductor inverted relative to their positions as shown in FIG. 2. In this inverted position of the carrier, the bridging conductor is inverted so that its contacts 13 become the lower contacts. The conductor can rock freely about the spring arm 37a for assuring good engagement of its contacts with the stationary contacts. The pressure holding the bridging conductors with their contacts 13 against the stationary contacts 9 when the switch parts are at rest is applied by the ledges 32 instead of by the spring arm 37a. In all other respects, the operation is the same.

Having thus described my invention, tI claim:

1. An electrical switch comprising a body, a pair of stationary contacts carried thereby, a contact assembly including a movable conductor element having a pair of contacts complementary to the stationary contacts and movable into and out of contact relation therewith upon movement of the element toward and away from the stationary contacts, a movable carrier, operating means to move the carrier in opposite directions, respectively, detachable means mechanically connecting the element to the carrier for eifecting said movement of the element by the carrier upon movement of the carrier in said opposite directions, said detachable connecting means comprising a surface on the carrier engaging the longitudinal mid-portion of the element, shoulders at the opposite lateral margins of the surface and constraining displacement of the element transversely of its length, from the surface, a snap fastening spring C-clamp receivable on the carrier, transversely of the element and Surface open end foremost with one arm of the clamp bridging across the space between the shoulders and overlying the conductor element, and the other arm engaging the carrier at a location at the opposite side of the element from that engaged by said one arm and in spaced relation to said surface, and said arms being in resilient clamping engagement with the carrier.

2. A switch according to claim 1 wherein said carrier, at one lateral margin of the surface, has a socket open toward and transversely of the surface and element for receiving the free end portion of said one arm of the C-clamp endwise and constraining the received free end portion from swinging endwise of the element.

3. An electrical switch comprising a body, a pair of stationary contacts carried thereby, a contact assembly including a movable conductor element having a pair of contacts complementary to the stationary contacts and movable into and out of contact relation therewith upon movement of the element toward and away from the stationary contacts, a movable carrier, operating means to move the carrier in opposite directions, respectively, detachable means mechanically connecting the element to the carrier for effecting said movement of the element by the carrier upon movement of the carrier in said opposite directions, said detachable connecting means including a portion of the carrier against which the element rests in operating position, and a resilient snap spring clamp receivable, while resiliently deflected, on the carrier in a final operating position, and operable when so received and released to restore itself toward undeflected condition to engage the carrier and retain the conductor element in operating position, said resilient snap spring clamp and carrier having complementary shoulders interengageable with each other upon release of the clamp in final position to constrain the clamp from accidental removal.

4. An electrical switch comprising a body, a pair of stationary contacts carried thereby, a movable conductor element having a pair of contacts complementary to the stationary contacts, a carrier supporting said element for movement to efiect the contact making and breaking relation upon movement of the carrier in opposite directions toward and away from the stationary contacts, said carrier comprising a frame, an actuating member extending through the frame, guide means in the body, said member having a part at one face of the frame received in and guided by the guide means during movement of the member in opposite directions, and another part at the opposite face of the frame for moving the member in one direction, a return spring for returning the member to starting position, dead center leaf spring means interposed between the frame and said member for moving the frame with a snap action in opposite directions, selectively, by initial movement of the member in a direction opposite to that in which the carrier is to be moved, the opposite ends of the frame having surfaces for conductor elements, conductor elements disposed against said surfaces, respectively, and held in operating position thereby, said elements extending transversely of the frame and parallel to the plane of the frame, snap fastening spring clamps receivable on the frame in resilient snap-fastening engagement therewith and overlying the elements, respectively, and constraining them to remain against said surfaces.

5. An electrical switch comprising a body, a pair of stationary contacts carried thereby, a movable conductor element having a pair of contacts complementary to the stationary contacts, a movable carrier supporting the element for movement in opposite directions to contact making and breaking positions, respectively, said movable carrier having a surface facing in the same direction as one face of the carrier and against which the element is disposed, shoulders at opposite margins of the surface engaging the lateral margins of the element to prevent its displacement laterally from the surface, said carrier having a first open ended slot extending substantially normal to said surface and open at the side adjacent the surface and having its open end in said one face, said carrier having a second open ended slot at its opposite face extending laterally of the surface and with its open side facing in the same direction as said opposite face, and open at its outer end, a snap-fastening C-clamp receivable open end foremost on the carrier with one free end received through the open side of the first slot and the other free end received through the open end of the second slot, whereby said second arm is prevented from displacement laterally by the side Walls of the second slot, said one arm spanning from one of said shoulders on the carrier to the other for holding the element on said surface, and said other arm having a detent portion, and the carrier having a shoulder behind which the detent is received to prevent accidental withdrawal of the clamp.

6. An electrical switch comprising a body, a pair of stationary contacts carried thereby, a movable conductor element having a pair of contacts complementary to the stationary contacts, a movable carrier supporting the element for movement in opposite directions to contact making and breaking positions, respectively, a carrier frame having a surface facing in the same direction as one face of the frame and against which the element is disposed in operating position, shoulders at opposite margins of the surface engaging the lateral margins of the element to prevent its displacement laterally of the surface, said frame having a socket opening outwardly of the frame with its open end in said one face of the frame, the frame having another socket at its opposite face extending transversely of the surface and open at its outer end, a snap-fastening C-clamp receivable open end foremost on the frame with the free end of its arms received through the open ends of the sockets, respectively, with one arm spanning from one shoulder to the other of the frame and constraining the element to lie against the surface, and one arm having a detent portion, the frame having a shoulder behind which the detent portion is resiliently received, when the clamp is installed, to prevent accidental removal of the clamp.

N 0 references cited.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent Ne, 35017 471 I January 16 I 1962 Walter- C Kareh It is hereby certified that error appears in the above numbered patc ent requiring correction and that the said Letters Patent should read as corrected below.

Column 2 line 7,, for "of" read for column 3 line 0'5 after "27" insert intermediate I Signed and sealed this 1st day of May 1962 SEAL) Attest:

ERNEST SWIDER DAVID L. LADD Attesting Officer Commissioner of Patents 

